The long term objective of this project is to obtain a fundamental understanding of the surface and interface phenomena that are crucial for the development of improved dental restorative resin systems. This study will focus on the physical and chemical properties of the interfaces between adhesives and/or coatings with dentin, enamel, and dental composites. This project has six specific aims which include: (1) To study the fundamental properties of the interfaces between adhesives, coatings, and dental materials and determine the surface and interface phenomena that determine the performance of adhesives, coatings, and dental composites. (2) To assess experimental techniques to determine the best methods for obtaining information on the interfacial properties of interest in this project. (3) To investigate the interface between polymeric adhesives and the dental substrates of dentin and enamel. (4) To investigate the interface between dental coatings and fillers to be used in dental composites and to investigate the surface characteristics of components under consideration for use as dental composites. (5) To investigate the structure of the dentin and enamel surfaces under study by other members of the Program Project through complete surface characterization. (6) To predict, at least qualitatively, the chemical functionalities that adhesives, coatings, and dental composites should contain to achieve good performance characteristics. Adhesives, fillers, and coatings will include those currently available as well as those under development in other subprojects of this Improved Polymeric Restoratives through Molecular Design Program Project. The surface analysis techniques that will be used in this subproject are Electron Spectroscopy for Chemical Analysis; Auger Electron Spectroscopy; Scanning Auger Microscopy; Ion Scattering Spectroscopy; Fourier Transform Infrared Spectroscopy; Scanning, Transmission, and Scanning Transmission Electron Microscopy; and Energy-Dispersive X-Ray Spectroscopy.